The requirements for capabilities of writing or marking instruments have changed considerably throughout the years. Markers or pens were used primarily in the past as writing instruments and were capable of delivering only a single ink. However the state of the art has become much more diverse and writing instrument users, particularly children, are attracted by unique, multi-functional markers or pens, such as those described herein that are capable of delivering a plurality of fluids, e.g., inks of different colors, either separately or simultaneously.
Most prior art writing instruments, for example, conventional ball-point pens, produce only a single color written trace. People, especially children, are fascinated by colors. Therefore, writing instruments capable of producing written traces of multiple colors have been designed, for example, to encourage children to develop motor and writing skills. Multi-color pens that use an array of ink containers of different colors arranged within or around the periphery of a thick pen barrel, such as those described in U.S. Pat. Nos. 1,938,835; 3,765,780; and 6,685,373. Despite its functionality, the pen barrels are so thick that it is not easy for the small hand of a child to get a firm grip on it. Additionally, in order to change colors, the user must retract the refill in use and extend another refill. Therefore, the pens are difficult to use, especially for young children. Moreover, each written trace produced by such pens constitutes a single ink composition and is therefore uniformly patterned throughout the written trace. On the other hand, the Swirl™ crayons deliver multi-color traces that are not controllable. In addition, there are pencils (Confetti Pencils by Colorific, Sanford Corporation, Bellwood, Ill.) and multi-color gel pens on the market. These products suffer from the same shortcoming in that the color combination is not controllable.
Crayons that deliver multi-colored written traces have been developed. For example, Sanford Corporation L.P. (Bellwood, Ill.) produces Colorific® Splitz™ and Colorific® Swirl™ crayons, which deliver confetti and block patterned multi-colored written traces, respectively. Such crayons are well-received by children (and their teachers) because the produced written trace includes multiple colors, and the colors of the written trace can change as the user makes a written mark across a substrate such as paper.
However, multi-color markers are not common. Sanford Corporation manufactured a double-ended marker that can produce traces of a different color from each marker end. U.S. Pat. No. 3,887,287 describes a multi-color marking implement having a plurality of flat-faced, adjacent marking nibs communicating with a plurality of nib-wicks, containing inks of different colors. However, because each nib is squared and contains a flat end surface, only one nib at a time can be used to mark a substrate.
Hence, there is a desire to develop a marking/writing instrument that can apply multiple materials to a substrate surface, such as different color inks, opaque inks and highlighter (transparent colored) inks, opaque, cover-up inks (e.g., white-out), dry erase ink, and any combination thereof in a controllable manner.
A single, multi-functional marking/writing instrument containing a multi-sectional, round nib writing end relieves the burden of parents in carrying multiple color markers for their children. In other words, if a marker can produce different color traces in a controllable fashion, a parent may only need to carry one marker instead of a whole bundle of markers each of a single color.
All these needs are met by the multi-fluid delivery markers described herein.